DIMMs Do More DRAM

DRAM chip density continues to climb. But the hunger for more memory seems insatiable,
especially with virtual systems running on multicore processors. One way to get more
memory in a system is to support more memory sockets, though this
requires more motherboard space and more drivers.
Another is to use higher-density chips, yet this
can be more costly.

MetaRAM puts
a DDR3 cont rol ler
between the memory
socket and memor y
chips (see the figure).
This allows a reduction
of memory loads
because the controller
presents one load
while handling multiple
SDRAM chips. It also
permits the creation of
higher-density dualinline
memory modules
(DIMMs) using lowerdensity
memory chips.

And, it’s possible to
build a bigger DIMM,
essentially doubling the
capacity, using existing
memory chips. The
approach is applicable regardless of the memory chip capacity. Using higher-density chips
simply increases the capacity of the resulting DIMM. The controllers support x4 and x8
DIMM interfaces.